TROCHUS.—PtuateE V. 
THE waveD Trocuus. Shell imperforate, broadly co- 
noid, fawn-red, covered everywhere with a brown 
persistent densely fibrous epidermis; whorls slopingly 
convex, sculptured with short wrinkled ribs and a 
necklace-like row of nodules, margin conspicuously 
wave-tubercled ; base convexly flat, three- to four- 
ridged. 
Woop, Ind. Test. Supp. pl. 5. f. 1. 
Trochus gigas, Auton. 
Pomaulax undosus, Gray. 
Hab. California. 
Though so distinct a species from the preceding, the 
sculpture of 7. wadosus presents only a slight modifica- 
tion of that of 7’. gibberosus. The very characteristic waved 
tubercle with which the basal margin of each whorl is 
corded is a modified form of the nearly closed marginal 
scale of 7. gibberosus, seen in a ruder more undeveloped 
state in 7. Japonicus, and the general typical structure of 
the columella is the same. Messrs. Gray and Adams 
| nevertheless contrive to place them in different genera. 
